WO2007141980A1

WO2007141980A1 - Drive system for electrically driven dump truck

Info

Publication number: WO2007141980A1
Application number: PCT/JP2007/059456
Authority: WO
Inventors: Yasuo Tanaka; Tomohiko Yasuda; Takashi Yagyu; Yutaka Watanabe
Original assignee: Hitachi Construction Machinery Co., Ltd.
Priority date: 2006-06-06
Filing date: 2007-05-07
Publication date: 2007-12-13
Also published as: JP4440232B2; AU2007256116A1; US20090048064A1; JP2007326411A; US8265849B2; AU2007256116B2; DE112007000379T5

Abstract

A drive system for an electrically driven dump truck provides, when it normally travels, the operator with good operation feeling where the relationship between the amount of operation of an accelerator pedal and output horse power of an electric motor matches requirements, and the system has improved controllability when the truck travels in creeping speed to facilitate delicate positioning of the truck. Blocks (213-216) calculate target motor output horse power (Pm0) corresponding to operation of the accelerator pedal (1), blocks (221, 222) calculate target motor torque (Tr1R, Tr1L) based on the target motor output horse power (Pm0) and rotational speeds (ωR, ωL) of electric motors (12R, 12L), block (225) calculates a limitation value of acceleration torque (motor acceleration torque Trmax2) of the electric motors (12R, 12L) according the amount of operation of the accelerator pedal (1), and blocks (226, 227) select, as a motor torque command value (TrR, TrL), a smaller value of the acceleration limitation value and the target torque (Tr1R, Tr1L) and controls inverters (73R, 73L).

Description

Specification

Electric drive truck drive system

Technical field

TECHNICAL FIELD [0001] The present invention relates to a drive system for an electric drive dump truck, and in particular, drives a generator with a prime mover, drives an electric motor for traveling with electric power generated by the generator, and drives a large dump truck for traveling. About the system.

Background art

[0002] As described in Patent Document 1, for example, a drive system for an electrically driven dump truck includes a prime mover, an electronic governor that controls the rotational speed and torque of the prime mover, an AC generator driven by the prime mover, Power is supplied by this AC generator to drive, for example, two electric motors that drive the left and right rear wheels, and two AC motors that are connected to the AC generator and control two electric motors (for example, induction motors) 2 Calculates the target rotational speed according to the operation amount of the two inverters and the accelerator pedal, controls the electronic governor, calculates the torque command values of the two electric motors according to the operation amount of the accelerator pedal, and calculates the torque command A control device for controlling the two inverters based on the values and for controlling the respective electric motors is provided.

[0003] Patent Document 1: Japanese Patent Laid-Open No. 2001-107762

Disclosure of the invention

Problems to be solved by the invention

[0004] In a conventional electrically driven dump truck, as described in Patent Document 1, a torque command value of an electric motor is calculated according to an operation amount of an accelerator pedal, and based on this torque command value. In general, the inverter is controlled to control the torque of the electric motor. However, when the electric motor is controlled in this way, the amount of operation of the accelerator pedal is not directly linked to the output horsepower of the electric motor, so that the operation feeling when the accelerator pedal is depressed is good. In order to solve such a problem, the target output horsepower of the electric motor is calculated according to the amount of operation of the accelerator pedal, and the target output horsepower is divided by the number of revolutions of the electric motor at that time to obtain the target of the electric motor. It is conceivable to calculate the torque (torque command value). However, if this is done, there are the following problems. [0005] During normal travel, such as when the dump truck is moved to another location, by calculating the target output horsepower of the electric motor according to the amount of operation of the accelerator pedal and controlling the electric motor, The relationship between the amount of operation and the output horsepower of the electric motor becomes the same, and a good operation feeling can be obtained. However, the dump truck traveling operation includes a traveling operation in which the dump truck is moved at a low speed and positioned, such as when the dump truck is stopped at the loading position near the excavator or the dump truck is placed on a load meter. is there. During such a driving operation, if the electric motor is controlled by calculating the target output horsepower of the electric motor according to the amount of operation of the accelerator pedal, the motor torque and its torque change will be excessive, so control during slow speed driving It becomes difficult to move the dump truck at a low speed and to position it at a desired position.

[0006] The object of the present invention is to obtain a good operational feeling in which the relationship between the amount of operation of the accelerator pedal and the output horsepower of the electric motor coincides with each other during normal traveling, and enhances the controllability during low-speed traveling. It is an object to provide a control system for an electrically driven dump truck that can be easily positioned.

Means for solving the problem

[0007] (1) In order to achieve the above object, the present invention provides a motor, an AC generator driven by the motor, and at least 2 for driving driven by electric power supplied from the AC generator. A motor that is connected to the AC generator, controls at least two inverters that control the electric motor, and controls the inverter according to the amount of operation of an accelerator pedal, respectively. And a motor target output horsepower calculating means for calculating a motor target output horsepower according to an operation amount of the accelerator pedal, and a motor target output horsepower. Motor target torque calculating means for calculating a motor target torque based on the rotational speeds of the two electric motors; and the accelerator pedal Acceleration torque limit value calculating means for calculating an acceleration torque limit value of the two electric motors according to the operation amount, and when the acceleration torque limit value is larger than the motor target torque, the motor target torque is converted into a motor torque. When the acceleration torque limit value is smaller than the motor target torque, the acceleration torque limit value is selected as the motor torque command value. Motor torque command value determining means and inverter control means for controlling the inverter based on the motor torque command value are provided.

[0008] In the present invention configured as described above, the acceleration torque limit value calculation means! The acceleration torque that is larger than the motor target torque with respect to the amount of operation of the accelerator pedal during normal traveling is determined. A limit value is calculated, and an acceleration torque limit value that is smaller than the motor target torque is calculated for the amount of accelerator pedal operation during slow speed travel. The target torque is selected as the motor torque command value, and the acceleration torque limit value is selected as the motor torque command value during slow speed travel. As a result, during normal running, a good operational feeling is achieved in which the relationship between the amount of operation of the accelerator pedal and the output horsepower of the electric motor is matched by running control based on the motor target output horsepower calculated by the motor target output horsepower calculation means. When the vehicle is traveling at a low speed, good controllability can be obtained by traveling control based on the acceleration torque limit value calculated by the acceleration torque limit value calculating means, and delicate positioning can be easily performed.

[0009] (2) In the above (1), preferably, the acceleration torque limit value calculating means lowers the acceleration torque limit value suitable for low-speed running when the accelerator pedal operation amount is zero. When the accelerator pedal operation amount is in a range including a fine operation region from 0 to an intermediate operation amount, the acceleration torque limit value increases as the accelerator pedal operation amount increases. The acceleration torque limit is set so that the acceleration torque limit value increases to the maximum torque as the minimum torque force increases to a higher torque in the torque range suitable for low speed driving and the accelerator pedal operation amount further increases. Based on the value characteristic, the acceleration torque limit value is calculated.

[0010] Thereby, in the motor torque command value determining means, the motor target torque is selected as the motor torque command value during normal travel, and the acceleration torque limit value is selected as the motor torque command value during slow speed travel. Is done.

[0011] (3) In the above (1), it is preferable that the lower torque in the torque range suitable for the low speed running is a motor allowable maximum torque of 15 preset in accordance with the rotational speed of the electric motor. The higher torque in the torque range suitable for the low speed running is 30% to 50% of the motor allowable maximum torque, and the intermediate operation amount is 40% to 6% of the maximum operation amount. 0%.

Thus, in the motor torque command value determining means, within the range of the maximum allowable motor torque, the motor target torque is selected as the motor torque command value during normal running and the acceleration torque limit is set during slow speed running. The value is selected as the motor torque command value.

[0013] (4) In the above (1), preferably, the acceleration torque limit value calculation means calculates a motor acceleration torque corresponding to an operation amount of the accelerator pedal as the acceleration torque limit value, and The motor torque command value determining means compares the motor target torque, the motor acceleration torque, and a motor allowable maximum torque set in advance according to the rotation speed of the electric motor, and selects the minimum value thereof.

Thus, the motor torque command value determining means selects the motor target torque as the motor torque command value during normal running and the acceleration torque limit during slow speed running within the range of the maximum allowable motor torque. The value is selected as the motor torque command value.

[0015] (5) In the above (1), the acceleration torque limit value calculating means calculates a motor torque limit ratio according to an operation amount of the accelerator pedal, and the motor torque limit ratio is calculated based on the motor torque limit ratio. In this case, the motor torque command value determining means may calculate the motor maximum torque, which is a value obtained by multiplying a preset motor allowable maximum torque according to the motor rotation speed, as the acceleration torque limit value. The motor target torque is compared with the motor maximum torque, and the minimum value thereof is selected.

Accordingly, in the motor torque command value determining means, the motor target torque is selected as the motor torque command value during normal running and the motor target torque is selected as the motor torque command value during normal running within the range of the maximum allowable motor torque. The acceleration torque limit value is selected as the motor torque command value.

(6) Further, in the above (1) to (5), preferably, a maximum horsepower calculating means for calculating a maximum horsepower usable by the electric motor for traveling according to the number of rotations of the prime mover. And a motor output for limiting the motor target output horsepower calculated by the motor target output horsepower calculating means so as not to exceed the maximum horsepower calculated by the maximum horsepower calculating means. The motor target torque calculating means calculates the motor target torque from the motor target output horsepower from the motor output horsepower limiting means and the rotation speeds of the two electric motors.

[0018] Thereby, for example, at the time of traveling acceleration, the motor speed is not sufficiently increased so that the motor target output horsepower calculated by the motor target output horsepower calculating means exceeds the maximum horsepower calculated by the maximum horsepower calculating means. Even in such a case, the motor target output horsepower is limited to the maximum horsepower, so that the motor stall can be prevented.

The invention's effect

[0019] According to the present invention, it is possible to obtain a good operation feeling in which the relationship between the operation amount of the accelerator pedal and the output horsepower of the electric motor coincides during normal running, and good controllability can be obtained during slow running, Subtle positioning can be easily performed.

Brief Description of Drawings

FIG. 1 is a diagram showing an overall configuration of an electric drive dump truck drive system according to an embodiment of the present invention.

FIG. 2 is a functional block diagram showing a processing procedure of the drive system according to the present embodiment.

FIG. 3 is a flowchart showing a processing procedure.

FIG. 4 is a flowchart showing a processing procedure.

FIG. 5 is a diagram showing a function Nrl (p) of the first target rotational speed when not traveling.

FIG. 6 is a diagram showing a function Nr2 (p) of the second target rotational speed during traveling.

FIG. 7 is a view showing a modification of the function Nr2 (p) of the second target rotational speed during traveling.

FIG. 8 is a diagram showing another modification of the function Nr2 (p) of the second target rotational speed during traveling.

FIG. 9 is a diagram showing a function Pmax (Ne) of motor maximum output horsepower.

[Fig. 10] Fig. 10 shows a data map of the speed vs. maximum motor output horsepower represented by the function f (Ne) and a data map of the speed vs. other motor load loss horsepower represented by the function g (Ne). It is a figure.

FIG. 11 is a diagram showing a function Pml (p) of a first motor target output horsepower during forward movement.

FIG. 12 is a diagram showing a function Pm2 (p) of the second motor target output horsepower during reverse travel. FIG. 13 is a diagram showing a relationship between a motor output target horsepower Pm, an electric motor rotational speed coR, coL, and a motor target torque TrlR, TrlL.

FIG. 14 is a diagram showing a data map of motor rotation speed vs. motor maximum torque represented by a function Trmaxl (ω) of motor maximum torque.

FIG. 15 is a diagram showing a function Trmax2 (p) of motor acceleration torque.

[FIG. 16] FIG. 16 is a diagram showing a selection result of minimum values of motor target torques TrlR, TrlL and motor acceleration torque Trmax2.

FIG. 17 is a functional block diagram showing a processing procedure of the drive system according to the second embodiment of the present invention.

FIG. 18 is a flowchart showing a processing procedure of the second embodiment.

FIG. 19 is a diagram showing a function Kmax (p) of a motor torque limit ratio.

Explanation of symbols

1 Accelerator pedal

2 retard pedal

3 Overall control unit

4 prime mover (diesel engine)

5 Alternator

6 Rectifier circuit

7 Inverter controller

8 Chopper circuit

9 Grid resistance

10 capacitors

11 Resistance for detecting the voltage after rectification

12R, 12L Left and right electric motors (induction motors)

13R, 13L reducer

14R, 14L Left and right rear wheels (tires)

15R, 15L electromagnetic pickup sensor

16 Shift lever 18 Other prime mover loads

71R, 71L Torque command calculator

72R, 72L Motor control calculation part

73R, 73L Inverter (switching element)

Nrl 1st target speed

Nr2 Second target speed

Nr target speed

Pml 1st motor target output horsepower

Pm2 Second motor target output horsepower

PmO motor target output horsepower

Pmax Motor output horsepower upper limit

Pm Motor target output horsepower

TrlR, TrlL Motor target torque

Trmax2 Motor power high speed Tonerek

Trmax Motor maximum allowable torque

TrR, TrL Motor torque command value

Function Nrl (p) First target speed characteristics

Function Nr2 (p) Second target speed characteristics

Function Trmax2 (p) Acceleration torque limit value characteristics

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing an overall configuration of a drive system for an electric drive dump truck according to a first embodiment of the present invention.

[0024] In Fig. 1, the drive system of the electric drive dump truck includes an accelerator pedal 1, a retard pedal 2, a shift lever 16, an overall control device 3, a prime mover 4, an alternator 5, and other prime mover loads 18. Circuit 6, Inverter controller 7, Chitsutsuba circuit 8, Grid resistor 9, Capacitor 10, Resistor 11, Left and right electric motors (eg induction motor) 12R, 12L, Reducer 1 3R, 13L, Tires 14R, 14L, Electromagnetic pickup Sensors 15R and 15L are provided. Inn The barter control device 7 includes torque command calculation units 71R and 71L, motor control calculation units 72R and 72L, and inverters (switching elements) 73R and 73L for the left and right electric motors 12R and 12L, respectively.

[0025] The operation signal p of the accelerator pedal 1 and the operation signal q of the retard pedal 2 are input to the overall control device 3, and are signals for controlling the magnitudes of the driving force and the retarding force, respectively.

[0026] When the dump truck moves forward or backward, when the accelerator lever 1 is depressed with the shift lever 16 in the forward position or the reverse position, the general control device 3 issues a command for the target rotational speed Nr to the prime mover 4. And the signal of the actual rotational speed Ne is returned from the prime mover 4 to the control device 3. The prime mover 4 is a diesel engine equipped with an electronic governor 4a. When the electronic governor 4a receives a command for the target rotational speed Nr, the fuel injection amount is controlled so that the prime mover 4 rotates at the target rotational speed Nr.

[0027] An AC generator 5 is connected to the prime mover 4 to perform AC power generation. The electric power generated by the AC power generation is rectified by the rectifier circuit 6, stored in the capacitor 10, and the DC voltage value becomes V. The AC generator 5 is controlled by the overall controller 3 so that the voltage value obtained by dividing the DC voltage V by the detection resistor 11 is feed-knocked so that the voltage value becomes a predetermined constant voltage VO.

[0028] The electric power generated by the AC generator 5 is supplied to the left and right electric motors 12R and 12L via the inverter control device 7. The overall control device 3 controls the AC generator 5 so that the DC voltage V rectified by the rectifier circuit 6 becomes a predetermined constant voltage VO, so that necessary electric power is supplied to the electric motors 12R and 12L. Control it.

[0029] Command horsepower MR, ML of left and right electric motors 12R and 12L from overall control device 3 Rotational speeds coR and coL of electric motors 12R and 12L detected by electromagnetic pickup 15R and 15L and force inverter control The inverter control device 7 is input to the device 7, and the torque command calculation unit 7 1R, 71L, the motor control calculation unit 72R, 72L, and the inverter (switching element) 73R, 73L with each slip motor> 0 Drives 12R and 12L.

[0030] Left and right rear wheels (tires) 14R, 14L are connected to the electric motors 12R, 12L via speed reducers 13R, 13L, respectively. The electromagnetic pickups 15R and 15L are usually sensors that detect the peripheral speed of one tooth of the gears in the reduction gears 13R and 13L. Also, for example, right drive Taking the system as an example, a detection gear may be attached to the drive shaft inside the electric motor 12R or the drive shaft connecting the speed reducer 13R and the tire 14R, and installed at that position.

[0031] When the accelerator pedal 1 is returned and the retard pedal 2 is depressed during traveling, the overall control device 3 controls so that the AC generator 5 does not generate power. Further, the horsepower commands MR and ML from the overall control device 3 are negative values, and the inverter control device 7 applies braking force to the traveling vehicle body by driving the electric motors 12R and 12L with a slip rate <0. At this time, each of the electric motors 12R and 12L acts as a generator and charges the capacitor 10 by a rectification function built in the inverter control device 7. The chopper circuit 8 operates so that the DC voltage value V is less than or equal to the preset DC voltage value VI, and current is passed through the grid resistor 9 to convert the electrical energy into heat energy.

[0032] In addition to the AC generator 5, the prime mover 4 is a hydraulic pump for driving a hydraulic system for raising and lowering the vessel of the dump truck and performing a steering operation (hereinafter referred to as a working hydraulic pump). 18a, a cooling fan (not shown) for sending air to the radiator, an AC generator 5, grid resistor 9, electric motors 12R, 12L, control devices 3, 7 etc. For example, a second generator or the like is driven. Figure 1 shows these as other prime mover loads 18.

[0033] The above is the basic configuration and operation of a normal electric drive dump truck.

[0034] Next, the parts that characterize the present invention will be described.

In the present invention, the operation of each component device is calculated according to a processing procedure in a memory, not shown, incorporated in the overall control device 3 and the inverter control device 7. FIG. 2 is a functional block diagram showing the processing procedure, and FIGS. 3 and 4 are flowcharts showing the processing procedure. Hereinafter, the processing procedure will be described mainly using the functional block diagram of FIG. 2 in accordance with the flowcharts shown in FIGS.

In FIG. 3 and FIG. 4, the processing flow starts from START and returns to STA RT again when processing up to END.

[0037] In step 101, the state amount S indicating the switching position of the shift lever 16, the operation amount of the accelerator pedal 1 (hereinafter referred to as the accelerator operation amount) p, the actual rotational speed Ne of the prime mover 4, and the electric motor 12R for traveling , 12L rotation speed (hereinafter referred to as motor rotation speed) coR, co L is read. Shift There are three positions for switching the bar 16: N (neutral), F (forward), and R (reverse).

[0038] In step 102, the accelerator operation amount p read in step 101 is calculated as the accelerator operation amount vs. the prime mover target rotation number expressed by the function Nrl (p) of the first target rotation speed during non-travel shown in FIG. Referring to the data map, the corresponding first target rotational speed Nrl is calculated (block 2 01 in FIG. 2).

[0039] The function Nrl (p) is the first target rotational speed characteristic suitable for driving the working hydraulic pump 18a. In FIG. 5, the function Nrl (p) indicates that the operation amount of the accelerator pedal 1 is not operated. The first target speed Nrl is the minimum speed Nrlmin (corresponding to the idling speed) of the prime mover 4, and the accelerator operation amount p is from 0 to the operation amount pa before the maximum operation amount pmax. When it is within the range, the first target speed Nrl increases from the minimum speed Nrlmin to the maximum speed Nrlmax as the operation amount p of the accelerator pedal 1 increases, and the accelerator operation amount p decreases the operation amount pa. If exceeded, the first target speed Nrl is set to be constant at the maximum speed Nrmlax. The minimum rotation speed Nrlmin is, for example, a rotation speed within a range of 700 rpm to 800 rpm, and is 750 rpm in the illustrated example. The maximum rotational speed Nrlmax is preferably the maximum rated rotational speed of the prime mover 4 and is, for example, a rotational speed within a range of 1800 rpm to 2100 rpm, and is 1900 rpm in the illustrated example.

[0040] Further, the operation amount pa before the maximum operation amount pmax is preferably an operation amount of 80% to 95% of the maximum operation amount pmax, and is 90% of the maximum operation amount pmax in the illustrated example.

[0041] In step 103, the accelerator operation amount p read in step 101 is set to a value of the accelerator operation amount vs. the prime mover target rotation number represented by the function Nr2 (p) of the second target rotation speed during traveling shown in FIG. The corresponding second target rotational speed Nr2 is calculated with reference to the data map (block 202 in FIG. 2).

) o

[0042] The function Nr2 (p) is a second target rotational speed characteristic suitable for driving the electric motors 12R and 12L. In FIG. 6, the function Nr2 (p) is the 0 when the operation amount of the accelerator pedal 1 is not operated. When the second target rotational speed Nr2 is the minimum rotational speed Nr2min (equivalent to the idle rotational speed) and the operating amount of the accelerator pedal 1 becomes the micro operating amount Pb 1. The second target rotational speed increases stepwise up to the medium speed rotational speed Nr2mid, and when the accelerator operation amount p is within the range from the slight operation amount Pb1 to the intermediate operation amount Pb2, the accelerator operation amount is As the speed increases, the second target speed Nr2 increases from the medium speed Nr2mid to the maximum speed Nr2max, and when the accelerator operation amount p exceeds the intermediate operation amount Pb2, the second target speed Nr2 becomes the maximum speed Nr2max. Is set to be constant! As in the case of the function Nrl (p), the minimum rotational speed Nr2min is, for example, a rotational speed within a range of 700 rpm to 800 rpm, and is 750 rpm in the illustrated example. The maximum rotation speed Nr2max is preferably a rotation speed within a range of 1800 rpm to 21 OO rpm, and in the illustrated example, is the same as the maximum rotation speed Nrlma X of the function Nrl (p), which is 1900 rpm which is the maximum rated rotation speed. When the minimum rotation speed Nr2min is 750 rpm and the maximum rotation speed Nr2max is 1900 rpm, the medium speed rotation speed Nr2mid is preferably a rotation speed within a range of 900 rpm to 1600 rpm, and in the illustrated example, 1300 rpm. Even if the minimum speed Nr2min and the maximum speed Nr2max are values other than 750 rpm and 1900 rpm, the medium speed Nrm2id can be set to a speed within the range of 900 rpm to 1600 rpm.

Further, the minute operation amount Pb 1 is preferably an operation amount within a range of 2 to 8% of the maximum operation amount Pmax of the accelerator pedal, and is 5% of the maximum operation amount pmax in the illustrated example. The intermediate operation amount Pb2 is preferably an operation amount within the range of 30 to 70% of the maximum operation amount Pmax, and in the example shown in the figure, it is 40% of the maximum operation amount Pmax.

FIG. 7 and FIG. 8 are diagrams showing modifications of the function Nr2 (p) during travel. In the example of Fig. 6, the maximum speed Nrlmax of the running function Nr2 (p) is the force set to the same value as the maximum speed Nrlmax of the non-traveling function Nrl (p). It may be a value lower than the maximum rotational speed Nr max (maximum rated rotational speed) of p), for example, 1800 rpm. In the example of FIG. 6, the second target speed Nr2 is set to the minimum speed Nr2min when the operation amount of the accelerator pedal 1 is in the range from 0 to the minute operation amount Pbl. As shown in FIG. 6, the operation amount range in which the second target rotational speed Nr2 is the minimum rotational speed Nrmin may be eliminated. In the example of Fig. 10, when the operation amount of accelerator pedal 1 is 0, the second target rotation speed Nr immediately becomes a medium speed rotation speed Nr2mid higher than the idle rotation speed, and thereafter, the accelerator operation amount p is 0 to the intermediate operation amount. The second target rotational speed Nr2 is set to increase from the medium speed rotational speed Nr2 mid to the maximum rotational speed Nr2max as it increases to Pb2.

[0045] In steps 104 to 106, the state quantity S of the shift lever 16 read in step 101 is N (medium If the state quantity S of the shift lever 16 is F (forward) or R (reverse), set the target speed Nr of the prime mover 4 to Nr. Put = Nr2 (block 203 in Figure 2).

[0046] In step 111, the actual rotational speed Ne of prime mover 4 read in step 101 is the data of engine rotational speed vs. motor maximum output horsepower represented by the function Mr (Ne) of the motor maximum output horsepower shown in FIG. Referring to the map, calculate the corresponding maximum horsepower Mr that can be used with the electric motors 12R, 12L, and multiply this by 1Z2 to calculate the output horsepower upper limit value Pmax per electric motor 12R, 12L ( (Blocks 211, 212 in Figure 2).

In FIG. 9, the function Mr (Ne) is the maximum horsepower that can be used by the electric motors 12R and 12L as the Ne increases (hereinafter referred to as the engine speed) (hereinafter referred to as the motor maximum output horsepower). Mr. and Mr. are set to increase.

A method for setting the function Mr (Ne) of the motor maximum output horsepower will be described.

[0049] FIG. 10 shows a data map of the speed vs. maximum motor output horsepower represented by the function f (Ne) and a data map of the speed vs. other motor load loss horsepower represented by the function g (Ne). FIG.

[0050] The function f (Ne) is the maximum output horsepower that can be generated by the prime mover 4, and is a synthesis of the function fl (Ne), the function f2 (Ne), and the function f3 (Ne). The function f 1 (Ne) corresponds to the function fr = f (Nr) of the target speed Nr of the prime mover 4 and the output horsepower, and the engine speed Ne is changed from Nrmin (for example, 750 rpm) to Nrmax (for example, 2000 rpm). The maximum output horsepower f (Ne) that the prime mover 4 can output changes to the minimum value Fmin force to the maximum value Fmax. This is a characteristic diagram unique to the prime mover 4. The function f2 (Ne) is the constant of f2 = Fmin with the maximum output horsepower f (Ne) of the prime mover 4 in the range of 0≤Ne Nrmin, and the function f3 (Ne) is Nrma x <Ne Within the range of ≤ Nemax! The maximum output horsepower f (Ne) of prime mover 4 is a constant value of f 3 = Fmax.

The prime mover 4 drives other prime mover loads 18 in addition to the AC generator 5. Other prime mover loads 18 include a hydraulic pump 18a for driving the hydraulic system for raising and lowering the vessel of the dump truck and steering operation, a cooling fan (not shown) for sending air to the radiator, and an AC generator 5, grid resistance 9, electric motor 12R, 12L, control A second generator (not shown) for driving an electric fan (not shown) for cooling the control devices 3, 7 and the like. The value of the horsepower assigned in advance to drive the other prime mover load 18 is g (Ne) in FIG. This horsepower g (Ne) is set to a large value with a margin with respect to the horsepower value actually consumed by the other motor load 18. In this specification, this horsepower is referred to as lost horsepower.

[0052] The loss horsepower function g (Ne) is a synthesis of the function gl (Ne), the function g2 (Ne), and the function g3 (Ne), like the function (Ne). In the function gl (Nr), when the engine speed Ne changes from Nrmin (for example, 750 rpm) to Nrmax (for example, 2000 rpm), the loss horsepower gl (Ne) changes from the minimum value Gmin to the maximum value Gmax. The function g2 (Ne) is obtained by setting the loss horsepower g (Ne) to a constant value of g2 = Gmin in the range of 0≤Ne and Nrmin, and the function g3 (Ne) is Nr max and Ne≤ Nemax. In this range, the loss horsepower g (Ne) is a constant value of g3 = Gmax.

[0053] In FIG. 10,! / Is the difference between f (Ne) and g (Ne) (f (Ne)-g (Ne)), and Mr is the total that Mr can give to the electric motors 12R and 12L. Effective maximum horsepower. In other words, Mr = f (Ne) —g (Ne) is the maximum horsepower (horsepower allocation) that can be used by the electric motors 12R, 12L for traveling out of the maximum output horsepower f (Ne) that the prime mover 4 can produce. Value), and the maximum output horsepower of the electric motors 12R, 12L cannot exceed that value, ie Mr = f (Ne)-g (Ne).

[0054] The function Mr (Ne) of the motor maximum output horsepower is set based on the above concept, and the output horsepower upper limit value Pmax per electric motor 12R, 12L is given by the following equation. It is done.

[0055] Pmax = Mr / 2 = (f (Ne) -g (Ne)) / 2

In step 112, the accelerator operation amount p read in step 101 is the data map of accelerator operation amount vs. motor target output horsepower represented by the function Pml (p) of the first motor target output horsepower during forward movement shown in FIG. Then, the corresponding first motor target output horsepower Pml is calculated (block 213 in FIG. 2).

[0056] In FIG. 11, the function Pml (p) is the first motor target output horsepower Pml = 0 when the accelerator operation amount p = 0, and Pml increases from the point XI in FIG. Increase the rate of increase in the force Pml near the point X2, so that the accelerator operation amount is less than the maximum value pmax. The maximum horsepower Pmlmax that can be generated by the electric motors 12R and 12L is set at the previous X3 point. The accelerator operation amount px3 at point X3 in Fig. 11 is about 95% of the maximum operation amount pma X, for example.

[0057] In step 113, the accelerator operation amount p read in step 101 is converted into a data map of the accelerator operation amount versus the motor target output horsepower represented by the function Pm2 (p) of the second motor target output horsepower during reverse travel. Referring to FIG. 2, the corresponding second motor target output horsepower Pm2 is calculated (block 214 in FIG. 2).

[0058] In FIG. 12, the function Pm2 (p) is the force that the second motor target output horsepower Pm2 increases as the accelerator operation amount p increases. The maximum value of the second motor target output horsepower Pm2max is the forward function Pml. The maximum value in (p) is set to be smaller than Pmlmax. The reverse motor target output horsepower may be obtained by multiplying the motor target output horsepower obtained by the forward function Pml (p) by a positive constant smaller than 1.

[0059] In steps 114 to 117, if the state quantity S of the shift lever 16 read in step 101 is N (neutral), the target horsepower (hereinafter referred to as the motor target output horsepower) P mO of the electric motors 12R and 12L is calculated. If PmO = 0 and the state quantity S of the shift lever 16 is F (forward), the target horsepower of the electric motor 1 2R, 12L (hereinafter referred to as the motor target output horsepower) PmO is set as PmO = Pml, and the shift lever 16 If the state quantity S is R (reverse), the motor target output horsepower PmO is set as PmO = Pm2 (blocks 215 and 216 in FIG. 2).

In step 118, the smaller value of the motor output horsepower upper limit value Pmax and the motor target output horsepower PmO is selected as the motor output target horsepower Pm (block 217 in FIG. 4).

[0061] Pm = min (Pmax, PmO)

That is, in step 118 (block 217 in FIG. 4), the final motor output target horsepower Pm force Pmax given to the electric motors 12R and 12L is limited so as not to exceed. This motor output target horsepower Pm corresponds to the command horsepower MR, ML shown in Fig. 1 (MR = ML = Pm

) o

[0062] In step 121, the motor target torques TrlR and TrlL are calculated from the motor output target horsepower Pm and the rotational speeds coR and coL of the electric motors 12 R and 12L read in step 101 by the following formula (Fig. 4 blocks 221, 222). [0063] TrlR = Kl X PmZ oR

TrlL = Kl X Pm / co L

Kl: Constant for calculating torque from horsepower and rotation speed.

FIG. 13 is a diagram showing the relationship between the motor output target horsepower Pm, the rotational speeds coR and coL of the electric motors 12R and 12L, and the motor target torques TrlR and TrlL. When the motor output target horsepower Pm is determined, the motor target torques TrlR and Trl L corresponding to the motor rotational speeds coR and coL at that time are determined. For example, when the motor rotation speeds coR and co L are ω 1, the motor target torques are TrlR = Pm (co l) and TrlL = Pm (ω 1). Also, for example, when the load torque of the electric motors 12R, 12L increases due to the force of the dump truck hitting the slope, and the motor rotation speed coR, co L decreases, the motor target torques TrlR, TrlL increase accordingly. . Conversely, when the motor load torque decreases, the motor target torque TrlR, TrlL is decreased. On the other hand, if the motor output target horsepower Pm increases, the motor target torques TrlR and TrlL increase accordingly. If the motor load torque at that time is constant, the motor rotational speeds coR and coL increase. Conversely, when the motor output target horsepower Pm decreases, the motor speed coR, coL decreases if the motor load torque is constant.

[0065] In step 122, the rotation speed coR, ω L of each of the electric motors 12R, 12L read in step 101 is converted into the motor rotation speed vs. motor maximum represented by the function Trmaxl (ω) of the motor maximum torque shown in FIG. Referring to the torque data map, calculate the corresponding maximum motor torque Trmaxl (blocks 223, 224 in Fig. 4).

In FIG. 14, the function Trmaxl (co) is the maximum current value that the inverters 73R and 73L can flow to the electric motors 12R and 12L, the output limits of driving elements such as IGBTs and GTOs in the inverters 73R and 73L, This is set based on the specifications of the devices that make up the drive system, such as the strength of the motor shaft. As shown in FIG. 14, for example, when the motor rotational speeds coR and coL are ω 1, the motor maximum torque Trmaxl is Trmaxl (ω 1). The maximum value of the motor maximum torque Trmaxl is Trmax.

[0067] In step 123, the accelerator operation amount p read in step 101 is referred to the accelerator operation amount vs. motor acceleration torque data map represented by the motor acceleration torque function Trmax2 (p), and the corresponding motor Calculate the acceleration torque Trmax2 (block 225 in Fig. 4). [0068] The function Trmax2 (p) is the acceleration torque limit value characteristic. In FIG. 15, the function Trmax2 (p) is the motor acceleration torque when the operation amount p of the accelerator pedal 1 is 0 (no operation). Trmax2 is a lower torque in the torque range suitable for slow speed driving, preferably the minimum torque Trmax2a, and when the accelerator pedal operation amount p is in the range including the fine operation range from 0 to the intermediate operation amount pc 1, As the accelerator operation amount p increases, the motor acceleration torque Trmax2 increases from the minimum torque Trmax2a to a higher torque range Trmax2b suitable for slow speed operation, and the accelerator operation amount p becomes the maximum operation amount pmax from the intermediate operation amount pel. When the accelerator operation amount p increases, the motor acceleration torque Trmax2 increases from the torque Trmax2b to the maximum torque that is the maximum motor maximum torque Trmaxl shown in Fig. 14. Until Trmax, increased at a rate higher than the range of operation amount 0～Pcl, § click cell operation amount P is the motor acceleration torque Trmax2 exceeds pc2 is set to so that constant and a maximum value Trmax. The torque range suitable for low-speed driving is considered to be about 15% to 50% of the maximum value Trmax (maximum allowable motor torque) Trmaxl shown in Fig. 14. The minimum torque Trmax2a is preferably Is 15% to 30% of the maximum value Trmax, and is 20% in the illustrated example. The higher torque T rmax2b in the torque range suitable for slow speed traveling is preferably 30% to 50% of the maximum value Trmax, and 40% in the illustrated example.

[0069] The intermediate manipulated variable pel is preferably 40% to 60% of the maximum manipulated variable pmax, and is 50% in the illustrated example. The operation amount pc2 at which the motor acceleration torque Trmax2 is maximized is preferably 70% to 95% of the maximum operation amount pmax, and is 80% in the illustrated example.

[0070] In step 124, the motor target torques TrlR and TrlL obtained in step 121 are compared with the motor maximum torque Trmaxl obtained in step 122 and the motor acceleration torque Trmax2 obtained in step 123. Select a value and use it as motor torque command values TrR and TrL (blocks 226 and 227 in Fig. 4). That is,

TrR = mm (Tr 1R, Trmaxl, Trmax2)

TrL = min (Tr 1 L, Trmaxl, Trmax2)

In Step 125, the engine target speed Nr obtained in Step 105 or 106 is commanded to the electronic governor 4a of the prime mover 4. In step 126, the motor torque command values TrR and TrL obtained in step 123 by the motor control arithmetic units 72R and 72L in the inverter controller 7 are commanded to the inverters 73R and 73L, and the electric motors 12R and 12L Torque control is performed.

[0072] The processing in steps 101 to 118 (blocks 201 to 217 in FIG. 4), the processing in step 123 (block 225 in FIG. 3), and the processing in step 125 are performed by the overall control device 3. The processes of 12 1, 122, 124 (blocks 221 to 224, blocks 226, 227 in FIG. 4) and step 126 are processes performed by the torque command calculation units 71R, 71L of the inverter control device 7.

In the above, the processing of steps 112 to 117 (blocks 213 to 216) constitutes a motor target output horsepower calculation means for calculating the motor target output horsepower PmO corresponding to the operation amount of the accelerator pedal 1, and the procedure 121 The processing of (blocks 221, 222) constitutes motor target torque calculation means for calculating the motor target torque TrlR, TrlL based on the motor target output horsepower PmO and the rotational speeds coR, coL of the electric motors 12R, 12L. The process of step 123 (block 225) constitutes an acceleration torque limit value calculation means for calculating the acceleration torque limit value (motor acceleration torque Trm _ax 2) of the electric motors 12R and 12L according to the operation amount of the accelerator pedal 1. If the acceleration torque limit value (motor acceleration torque Trmax2) is greater than the motor target torques TrlR and TrlL, the process of step 124 (blocks 226 and 227) is performed using the motor target torque as the motor torque command value. Selected as TrR, TrL When the acceleration torque limit value (motor acceleration torque Trmax 2) becomes smaller than the motor target torque TrlR, TrlL, the motor torque command value determining means selects the acceleration torque limit value as the motor torque command values TrR, TrL. The torque command calculation units 71R and 71L and the motor control calculation units 72R and 72L of the inverter control device 7 are based on the motor torque command values TrR and TrL. Inverter control means for controlling is configured.

[0074] The acceleration torque limit value calculating means (procedure 123, block 225) calculates the motor acceleration torque Trmax2 corresponding to the operation amount of the accelerator pedal 1 as the acceleration torque limit value, and the motor torque command value determining means (Procedure 124, Block 226, 227) compares the motor target torque TrlR, TrlL, the motor acceleration torque Trmax2, and the motor allowable maximum torque Trmax set in advance according to the rotation speed of the electric motors 12R, 12L. Select the minimum value of. [0075] Further, the processing of step 111 (blocks 211 and 212) constitutes a maximum horsepower calculating means for calculating the maximum horsepower Pmax that can be used by the electric motors 12R and 12L according to the rotational speed of the prime mover 4. The process of step 118 (block 217) is a motor output that limits the motor target output horsepower PmO calculated by the motor target output horsepower calculating means (steps 11 to 117, blocks 213 to 216) so as not to exceed the maximum horsepower Pmax. The motor target torque calculating means (procedure 121, blocks 221, 222) is composed of the motor output horsepower limiting means, the motor target output horsepower Pm and the rotational speeds of the electric motors 12R, 12L coR, co Calculate motor target torque TrlR, TrlL from L and force.

Next, the operation of the present embodiment will be described.

[0077] 1. When not driving

When not driving, set the shift lever 16 to the N (neutral) position. When the shift lever 16 is in the N (neutral) position, the target horsepower PmO of the electric motors 12R and 12L is PmO = 0, and the motor is not driven.

[0078] On the prime mover side, the data map of the function Nrl (p) of the first target rotational speed at non-travel shown in FIG. 5 is selected, and the first target rotational speed Nrl by the function Nrl (p) is It is given as the target speed Nr. For this reason, when the accelerator pedal 1 is not depressed, the target speed Nr of the prime mover 4 is 750 rp, which is the idling speed, and fuel consumption can be minimized and fuel consumption can be reduced. When the accelerator pedal 1 is depressed, the target speed Nr of the prime mover 4 increases from 750 rpm to the rated speed of 1900 rpm according to the depression amount, and the rotational speed of the prime mover 4 varies in a wide range from the minimum to the maximum. Therefore, when the work is performed with the dump truck stopped and only the hydraulic system operated, such as on a vessel, the prime mover 4 is operated stably and the maximum flow rate of the hydraulic pump 18a is ensured. The working speed can be adjusted.

[0079] 2. During normal driving

During normal driving, shift lever 16 is in the F (forward) position. When the shift lever 16 is set to the F (forward) position, the data map of the function Pml (p) of the first motor target output horsepower at the time of forward movement shown in FIG. The first motor target output horsepower Pml by the function Pml (p) is given as the motor target output horsepower PmO. [0080] On the prime mover side, the data map of the function Nr2 (p) of the second target rotational speed at the time of traveling shown in FIG. 6 is selected, and the second target rotational speed Nr2 by the function Nr2 (p) It is given as a target speed Nr of 4. For this reason, when the accelerator pedal 1 is not depressed, the target speed Nr of the prime mover 4 is set to the idle speed 750 rp, and the fuel consumption can be minimized and the fuel consumption can be reduced. In addition, if the accelerator pedal 1 is depressed even slightly at the start of driving, the target rotational speed Nr of the prime mover 4 immediately increases to the medium speed rotational speed of 1300 rpm, and then the target rotational speed of the prime mover 4 according to the depression amount of the accelerator pedal. Nr increases from 1300rpm to the maximum speed (rated speed) of 1900rpm. As a result, the rotational speed of the prime mover 4 changes with high response from the medium speed rotational speed to the maximum rotational speed, so that the responsiveness when the accelerator pedal 1 is depressed is improved, and good acceleration performance can be obtained.

[0081] Also, as shown in Fig. 7, when the maximum speed of the function Nr2 (p) is set to 1800rpm, which is lower than the rated speed of 1900rpm, for example, the output horsepower of the prime mover 4 falls slightly and the running speed drops slightly. However, fuel consumption during running can be reduced. There are many cases where the slope is small and only 5 to 7% when traveling on an uphill road with sediment and mining objects loaded on the vessel under conditions of the mine road. In such a case, some users demand that it is better to reduce the fuel consumption even if the traveling speed drops slightly. By setting the maximum speed to a speed lower than the rated speed, it is possible to meet such user requirements.

[0082] As shown in FIG. 8, when the operation amount of the accelerator pedal 1 is 0, the second target rotational speed Nr is immediately set to a medium speed rotational speed Nr2mid higher than the idle rotational speed. Even if the dull is not operated, the prime mover 4 is controlled by the medium speed Nr2mid, so the fuel consumption increases compared to the example in Fig. 6. However, in this case, the response when the accelerator pedal 1 is depressed is further improved, and the effect of further improving the acceleration performance during driving can be obtained.

[0083] On the electric motor side, when accelerator pedal 1 is depressed to the maximum, step 123! /, From the data map of motor acceleration torque function Trmax2 (p) shown in FIG. Since the maximum value Trmax of the maximum motor torque Trmaxl is obtained as the motor acceleration torque Trmax2, the motor acceleration torque Trmax2 is not a limitation for the control (running control) of the electric motors 12R and 12L. Therefore, the first motor target output calculated by step 112 is used. Since the electric motors 12R and 12L are controlled based on the horsepower Pml (motor target output horsepower PmO), there is a good operational feeling in which the relationship between the operation amount of the accelerator pedal 1 and the output horsepower of the electric motors 12R and 12L is consistent. can get.

[0084] Further, on the electric motor side, in step 111, the maximum horsepower Pmax that can be used in the electric motors 12R and 12L according to the rotational speed of the prime mover 4 is calculated. In step 118, the motor target output horsepower PmO is calculated. In order to limit the maximum horsepower Pmax so that it does not exceed the maximum horsepower Pmax, the motor target output can be increased even when the motor 4 output speed is not sufficiently increased and the motor target output horsepower PmO exceeds the maximum horsepower Pmax. Since the horsepower PmO is limited to its maximum horsepower Pmax, the stall of the prime mover 4 can be prevented.

[0085] 3. At low speed

When driving at a slow speed, set the shift lever 16 to the F (forward) position and depress the accelerator pedal 1 slightly. At this time, on the electric motor side, the first motor target output horsepower Pml is obtained as the motor target output horsepower PmO by the function Pml (p) of the first motor target output horsepower at the time of forward movement shown in FIG. The first target rotational speed Nrl obtained from the function Nrl (p) of the first target rotational speed during non-travel shown in FIG. 6 is obtained as the target rotational speed Nr of the prime mover 4 in the same manner as during normal travel.

[0086] Further, when the accelerator pedal 1 is slightly depressed on the electric motor side, if the depression amount is, for example, about 0 to 50%, the function of the motor acceleration torque shown in FIG. In Trmax2 (p), 20 to 40% of the maximum value Trmax of the maximum motor torque Trm axl is obtained as the motor acceleration torque Trmax2, and the target torque TrlR, TrlL, the maximum motor torque Trmaxl, and the maximum motor torque Trmax2 In step 124 for selecting the minimum value, the motor acceleration torque Trmax2 is selected as the motor torque command values TrR and TrL. For this reason, since the running torque and torque change when the accelerator pedal 1 is finely operated are suppressed, good controllability can be obtained during slow speed running, and delicate positioning can be easily performed.

FIG. 16 is a diagram showing a selection result of the minimum values of the motor target torques TrlR and TrlL and the motor acceleration torque Trmax2 in the procedure 124 (blocks 226 and 227). In the figure, A, B, C, D, and E correspond to points A, B, C, D, and E in FIGS. 11 and 15, respectively. [0088] When the accelerator operation amount is at points A, B, C, D, and E in FIG. 11, in step 121 (blocks 22 and 222), the values of A, B, C, D, and E in FIG. The motor target torques TrlRA, TrlLA to TrlRE, TrlLE (hereinafter referred to as TrlA) shown by the solid and dashed hyperbolic curves in Fig. 16 from the function Pml (p) of the first motor target output horsepower and the first motor target output horsepower corresponding to each point ~ (Abbreviated as TrlE). In addition, when the accelerator operation amount is at points A, B, C, D, and E in Fig. 15, the function Trmax2 (p) force of the motor acceleration torque is also shown by the solid line in Fig. 16 in step 123 (block 225). The motor acceleration torques Trmax2A to Trmax2E shown are calculated. In step 124 (blocks 226, 227), the smaller one of these values is selected, and the motor torque command values Tr R, TrL become the values shown by the solid lines in FIG.

In FIG. 16, the motor torque command values indicated by solid lines A, B, and C are those when the accelerator operation amount p is 50% or less, and the maximum values thereof are motor acceleration torques Trmax2A to Trmax2C. This keeps the motor maximum torque Trmaxl at a small value in the range of 20% to 40% of the maximum value Trmax. In addition, the change in the motor torque command value with respect to the change in the accelerator operation amount when the accelerator pedal is operated is also compared with, for example, ΔΤΑΒ1 and ΔΤΑΒ2 (ΔTAB1 and ΔΤΑΒ2), ATBC1 and ATBC2 (ATBC1 and ATBC2) As can be seen, the motor target torque TrlA to TrlE is reduced compared to the amount of change in the motor torque command value.

[0090] Thus, when the accelerator operation amount p is in the range of 50% or less, the maximum value of the motor torque command value is kept small, and the change of the motor torque command value with respect to the change of the accelerator operation amount when the accelerator pedal is operated is small. By being pressed down, the running torque and running torque change by the electric motors 12R and 12L when the accelerator pedal is operated are reduced, and the change in running speed is also reduced, so that the controllability during slow speed running can be improved.

[0091] As described above, according to the present embodiment, when the operation amount of the accelerator pedal 1 is 0 to 50%, the maximum torque for driving the electric motors 12R and 12L is suppressed to 20 to 40%. When the operation amount is 50% or more, the maximum torque is increased, and the limit value of the maximum torque is set to 100% before 100%, so that the operation amount of the accelerator pedal 1 and the output of the electric motors 12 R, 12L during normal driving A good sense of operation with the same relationship with horsepower is obtained, and when the amount of operation of the accelerator pedal 1 is small, the torque and torque change are limited to a low level, and good control is achieved at low speeds. Control can be obtained, and delicate positioning can be easily performed.

[0092] When the shift lever 15 is at the N position and the vessel is moved up and down without traveling, such as when driving the hydraulic system during non-traveling, the target rotational speed is, for example, 750 to 1900 rpm depending on the amount of operation of the accelerator pedal 1 And when the shift lever 16 is in the F or R position, the target rotational speed of the prime mover 4 is given in the range of 1300 to 1900 rpm, for example, depending on the accelerator pedal 1. The engine can be operated stably and the maximum flow rate of the hydraulic pump can be secured, and the working speed can be adjusted over a wide range, and the responsiveness when the accelerator pedal is depressed during driving improves the acceleration. Can be obtained. Even when the shift lever 16 is traveling in the F position or the R position, when the accelerator pedal 1 is not operated, the target rotational speed of the prime mover 4 is the minimum rotational speed, so that fuel consumption can be improved.

A second embodiment of the present invention will be described with reference to FIGS. In the present embodiment, instead of obtaining the accelerator operation amount force motor acceleration torque, the motor torque limit ratio is obtained.

FIG. 17 is a functional block diagram similar to FIG. 2, showing the processing procedure of the drive system according to the present embodiment. FIG. 18 is a flowchart showing the processing procedure, and corresponds to FIG. 4 in the first embodiment.

[0095] In the present embodiment, the control procedure on the prime mover side (procedures 101 to 106 in Fig. 3) and the procedure up to calculation of the motor maximum torque Tmaxl on the electric motor side (procedure in Fig. 3) The processing procedure from 111 to 122 in FIG. 4 is the same as that of the first embodiment. In the present embodiment, after calculating the motor maximum torque Trmaxl from the rotational speed coR, ωL of each electric motor 12R, 12L and the function Trmaxl (ω) of the motor maximum torque in step 122, in step 131, the accelerator With reference to the data map of the accelerator operation amount to motor torque limit ratio represented by the function Kmax (p) of the motor torque limit ratio shown in FIG. Calculate (Block 225A in Figure 17).

[0096] In FIG. 19, the function Kmax (p) is obtained by changing the vertical axis of the motor acceleration torque function shown in FIG. 15 to a limit ratio (100 fraction), and dividing the value into the motor allowable maximum torque Trmax. (%).

In step 132, motor maximum torque Trmax2 is calculated by multiplying motor maximum torque Trmaxl by motor torque limit ratio Kmax obtained in step 131 (blocks 231, 232 in FIG. 17).

[0098] In step 133, the motor target torques TrlR and TrlL are compared with the maximum motor torque Trmax2 obtained in step 132, and the minimum value thereof is selected and set as the motor torque command values T rR and TrL (Fig. 17 blocks 233, 234). That is,

TrR = min (Tr 1R, Trmax2)

TrL = min (Tr 1 L, Trmax2)

Subsequent steps 125 and 126 are the same as those in the first embodiment shown in FIG. 4. The engine target speed Nr is commanded to the electronic governor 4a of the prime mover 4, and the motor torque command values TrR and TrL are set to the inverter 73R. , Command 73L.

[0099] As described above, the processing of Tegawa pages 131, 132 (blocks 225A, 231, 232) is the same as the processing of step 123 (block 225) in the first embodiment. Configure the acceleration torque limit value calculation means to calculate the acceleration torque limit value (motor maximum torque Trmax2) of the electric motors 12R and 12L according to the operation amount of 1. The process of step 133 (blocks 233, 234) Similar to the processing in step 124 (blocks 226, 227) in the above embodiment, when the acceleration torque limit value (motor maximum torque Trmax2) is larger than the motor target torque TrlR, TrlL, the motor target torque is If the acceleration torque limit value (motor maximum torque Trmax2) is smaller than the motor target torque TrlR, TrlL, the acceleration torque limit value (motor maximum torque Trmax2) is set as the motor torque command value TrR, TrL. To select Configuring the torque command value determining means.

[0100] As described above [this embodiment], the processing functions of Tegawa pages 131, 132 (blocks 225A, 231, 232) and procedure 133 (blocks 233, 234) are the first This is the same as the processing function of step 1 23 (block 225) and step 124 (block 226, 227), and the relationship between the amount of operation of the accelerator pedal and the output horsepower of the electric motor coincides during normal driving. Operation feeling can be obtained, good controllability can be obtained during low-speed running, and delicate positioning can be easily performed. [0101] While one embodiment of the present invention has been described above, various modifications can be made within the spirit of the present invention. Some of them will be described below.

[0102] For example, in the above embodiment, in step 111 (block 211), the actual rotational speed N e of the prime mover 4 is referred to the function Mr (Ne) of the motor maximum output horsepower and can be used in the electric motors 12R and 12L. However, the actual speed Ne of the prime mover 4 is almost equal to the target speed Nr. Therefore, instead of the actual speed Ne of the prime mover 4, the target speed The maximum horsepower Mr that can be used with the electric motors 12R and 12L may be obtained using several Nr. In addition, the maximum horsepower Mr is set to 1Z2, and the output horsepower upper limit value Pmax per unit of the electric motors 12R and 12L is calculated. The power output value Pmax and the motor target output horsepower PmO After selecting the smaller value, the value may be halved to set the motor output target horsepower Pm.

[0103] Although the electric motors 12R and 12L are induction motors, they may be synchronous motors.

Claims

The scope of the claims

[1] Motor (4),

An alternator driven by this prime mover (5),

At least two electric motors (12R, 12L) for driving driven by power supplied from the AC generator;

At least two inverters (73R, 73L) connected to the AC generator and controlling the electric motor, respectively;

A drive system for an electrically driven dump truck having motor control means (3, 7) for controlling the inverter according to the operation amount (p) of the accelerator pedal (1) and controlling the electric motor. ,

The motor control means (3, 7)

Motor target output horsepower calculating means (112, 113, 213, 214) for calculating a motor target output horsepower (Pm) corresponding to the operation amount (p) of the accelerator pedal (1);

Based on the motor target output horsepower and the rotation speeds (coR, ωL) of the two electric motors (12R, 12L), a motor target torque calculation means (121) that calculates the motor target torque (TrlR, TrlL) , 221, 222) and

Acceleration torque limit value calculating means (123, 225) for calculating an acceleration torque limit value (Trmax2) of the two electric motors according to the operation amount (p) of the accelerator pedal (1);

When the acceleration torque limit value is larger than the motor target torque, the motor target torque is selected as a motor torque command value (TrR, TrL), and the acceleration torque limit value becomes smaller than the motor target torque. Motor torque command value determining means (124, 226, 227) for selecting the acceleration torque limit value as the motor torque command value (TrR, TrL);

A drive system comprising inverter control means (126, 71R, 71L, 72R, 72L) for controlling the inverter based on the motor torque command value.

[2] In the drive system for an electrically driven dump truck according to claim 1,

The acceleration torque limit value calculation means (123, 225) has a lower acceleration torque limit value (Trmax2) suitable for low speed driving when the operation amount (P) of the accelerator pedal (1) is 0. It is torque, and the operation amount of the accelerator pedal is fine operation from 0 to the intermediate operation amount When the accelerator pedal operation amount increases, the acceleration torque limit value (Trmax2) is a torque that is higher in the torque range suitable for low speed driving than the minimum torque force. Based on the acceleration torque limit value characteristic (Trmax2 (p)) set so that the acceleration torque limit value (Trmax2) increases to the maximum torque when the accelerator pedal operation amount further increases, A drive system that calculates the acceleration torque limit value (Trmax2).

[3] In the drive system of the electric drive dump truck according to claim 2,

The lower torque in the torque range suitable for the low speed running is 15% to the maximum allowable motor torque (Trmax) set in advance according to the rotation speed (ωR, ωL) of the electric motor (12R, 12L). The higher torque in the torque range suitable for the low-speed driving is 30% to 50% of the maximum motor allowable torque (Trmax), and the intermediate operation amount is 40% to 60% of the maximum operation amount. The drive system characterized by being.

[4] In the drive system of the electric drive dump truck according to claim 1,

The acceleration torque limit value calculating means (123, 225) calculates a motor acceleration torque corresponding to the operation amount (p) of the accelerator pedal (1) as the acceleration torque limit value (Trmax2), and the motor torque command value The determination means (124, 226, 227) is configured to set a motor allowable maximum torque (Trmax) set in advance according to the motor target torque (Tr 1R, TrlL), the motor acceleration torque (Trmax2), and the rotational speed of the electric motor. A drive system characterized in that the minimum value is selected.

[5] In the drive system of the electric drive dump truck according to claim 1,

The acceleration torque limit value calculating means (131, 225A) calculates a motor torque limit ratio (Kmax) corresponding to the operation amount (P) of the accelerator pedal (1), and calculates the motor torque limit ratio to the electric motor ( 12R, 12L) is calculated as the acceleration torque limit value (Trmax2), which is a value obtained by multiplying the preset motor allowable maximum torque (Trmax) according to the rotation speed (coR, coL).

The motor torque command value determining means (133, 233, 234) compares the motor target torque (Tr 1R, TrlL) with the motor maximum torque and selects the minimum value thereof. Driving system. In the drive system of the electric drive dump truck according to claim 1 or claim 1!

Furthermore,

Maximum horsepower calculating means (111, 211, 212) for calculating the maximum horsepower (Mr) that can be used by the electric motor (12R, 12L) for traveling according to the rotational speed of the prime mover (4);

Motor output for limiting the motor target output horsepower (Pm) calculated by the motor target output horsepower calculating means (112, 113, 213, 214) so as not to exceed the maximum horsepower calculated by the maximum horsepower calculating means. Horsepower limiting means (118, 217),

The motor target torque calculation means (121, 221, 222) is calculated from the motor target output horsepower from the motor output horsepower limiting means and the rotational speeds (coR, coL) of the two electric motors (12R, 12L). Drive system characterized by calculating motor target torque (TrlR, TrlL).